Symbiotic Fantasy
by Smoky Opium
Summary: We know that according to Canon, Sebastian made himself into the perfect butler for Ciel. But what if the opposite was actually true? What if there was a creature that lived by becoming another creature's ultimate fantasy? (please note that due to the graphic nature of the last scene, this story has not been completely published. Please see my AO3 site for the complete story)


**Disclaimer:** Kuroshitsuji (Black Butler) © Yana Toboso. No profit is being made from this story. This story does not necessarily reflect the author's religious views, beliefs or morals.

 **Rating:** AV15+

 **Warning:** May contain spoilers. Gore. Vore. Dark themes. Psychological – Manipulation & Obsession. Non-explicit sex scene. Yaoi/Slash/Shounen-Ai.

 **Summary:** We know that according to Canon, Sebastian made himself into the perfect butler for Ciel. But what if the opposite was actually true? What if there was a creature that lived by becoming another creature's ultimate fantasy?

 **Story type:** Manga cannon reflective AU.

 **Pairing:** Demon!Sebastian/Dream-Fantasy!Ciel

 **AN (may contain spoilers for story and cannon):** This particular idea cropped up while I was contemplating the relationship between Sebastian and Ciel. Then I started thinking of Ciel and his back story and I wondered; his backstory is a stereo typical type tragedy, what are the chances that someone of Ciel's back ground would go through that particular situation and call out for a demon and that a demon would actually be listening? It's too good to be true. Combined with "Dressin' Up" by Katy Perry playing in the background, that train of thought lead to this story. I have also taken some liberties about Ciel's office. I'm not 100% sure about how it's supposed to look and anime screenshots can only help so much. I really enjoyed writing this. I think it could be longer and the plot line better developed. There were also parts and events which I can sense lurking just beyond my reach. So while I'm not entirely happy with how it has turned out, I'm satisfied with the result.

 **Historical note:** The biological term "Symbiosis" was coined in 1876, possibly stemming from an earlier word used to refer to communal living, in the 1620's. However the first recorded use of its adjective form "Symbiotic" wasn't recorded until 1882. This just fits the Manga canon timeline which pegs Ciel as being born in 1875, setting the manga around 1888.

 **Symbiotic Fantasy**

Sebastian was a perfect butler; unnaturally beautiful, perfectly graceful with lightning reflexes. There was nothing that he could not do if he put his mind to it. Coupled up with the fact that he was part of the supernatural, his breadth of knowledge made him superior to even the most learned human. It was a constant tussle between master and servant for Ciel to make his perfect butler trip up.

Ciel was in many ways the perfect prey; young, dependent, relatively weak, impressionable, and vengeful to the point of leasing his soul.

A little _too_ perfect one could say.

The Earl and The Butler; Ciel Phantomhive and Sebastian Michealias; The Human and The Demon; the Prey and it's Hunter.

Sebastian had never questioned the perfection of his master's soul. Ciel's soul was like a prime cut of meat, all it needed was the seasoning. But a prime cut of meat is created intentionally; it needs to have the tendons and other distasteful bits cut off, trimmed and prepared for cooking at the correct temperature. Such a soul as that belonging to the creature known as Ciel Phantomhive would have had to be created in much the same manner. Which brings up another question; who could have created such a soul? An obvious candidate at first glance are the Shinigami, those in the business of reaping souls. Could they have created Ciel as bait to trap a demon? It is plausible; by occupying the demon you would reduce the number of souls which go missing. However the Shinigami are in the business of _taking_ souls not _giving_ them. Well unless you're a rogue Shinigami, but even then the bizarre dolls didn't have new souls.

Humans. The advances with science have been extraordinary, creating super humans with extraordinary strength, imprisoning and tricking innocents into creating deadly chemicals. Truly human cruelty and greed knows no bounds; is it really a stretch of the imagination to think that they would create a creature, make it believe it was human, put it through terrible experiences, psychologically torture it, just to catch such a fantastical creature as a demon? However if this was the case, the incident with the bizarre dolls wouldn't have gone so very wrong.

That leaves us one more; demons. There are more demons out there than just Sebastian; he is not The Devil, but a demon, indicating that there are others like him. But what purpose would a demon have to make a soul. Demon politics? And if they could make souls, why not eat it themselves? No, demons didn't fashion Ciel Phantomhive.

So who did? Then it dawns, the revelation; no-one. There is a fourth category that hasn't been introduced yet. A creature unknown, something that lurks in the depths of all sentient creature's minds and even in a few who are not. Something that exists by becoming the ultimate fantasy of a creature, existing to fulfil its whims and sate its desires.

§§§

The revelation of this to Sebastian came about purely by accident. It was Sebastian's routine to retreat to his room during the night, simulating sleeping. It was interesting, since a creature such as he needed no sleep, but it was amusing to see what his human copy of a brain would come up with. He had been preparing for bed when the thought, no, wish came to him. The last few days had been boring; no missions from the Queen for his little master, no assassins for him to deal with. Even the servants had been unusually well behaved, but in his mind this only meant that the fallout later would be that much greater.

 _Humans are so predictable sometimes. I wish the young master would show me something interesting._

It was just a fleeting thought, barely even a whisper of a wish, but it was enough. There was a knock on the door. Raising an eyebrow to himself, Sebastian opened the door, expecting to see one of the servants. The cold gaze of his master met his eyes. Pasting a pleasant smile on his face Sebastian knelt down in front of his master.

'Is there something you need, young master? You could have rung for me. It is unfitting for the young master to be here at this time of night.'

Ciel cocked his head to one side, his wide blue eyes staring at Sebastian. Suddenly, faster than Sebastian had anticipated, one small hand shot out and fisted it's self in his shirt collar. Sebastian found himself yanked forwards, Ciel soft breaths fanning his face.

'Make me feel I'm alive Sebastian.' Ciel whispered before pressing his lips to Sebastian's, biting the demon's lower lip.

In a whirlwind of movement, Sebastian had Ciel on the floor, his heavier body crushing the frail form into the floor. One hand slammed into the floor next to the doll like face while the other seized the delicate jaw forcing the younger to look into the eyes of the demon. He hovered over the boy, his fringe shadowing his face leaving only the glow of his demonic eyes and the glint of his preternaturally sharp teeth.

'What are you?' the demon rumbled.

'Your master you oaf!' Ciel shouted back, his hands slapping ineffectually at the demon. The demon rose in a blur of movement lifting the boy up by his neck, before slamming him into a wall.

'You lie! You are not him! This is not how he behaves!' He roared, holding the flailing figure with ease.

'I order you to let me go!' Ciel rasped out, choking as the demon crushed his windpipe. Sebastian felt the familiar burn on the back of his left hand that signified to enforcement of the order. He dropped Ciel, frowning at the huddled heap on the floor that gasped for breath.

'Forgive me master. But your request was not like you at all.' There was a thoughtful silence as Ciel's breathing calmed down.

'You're not human.' The demon stated looking down dispassionately.

'What on earth are you talking about Sebastian?' Ciel gasped, getting to his feet.

'If you were human, you wouldn't have been able to withstand me slamming you into the wall. Nor should you have been able to recover so quickly from a potential asthma attack.' The demon reasoned looking at his young charge through slitted eyes.

'Furthermore you move faster than a demon; I didn't even see your hand move when you grabbed my shirt. So what are you?' The boy just stared expressionlessly at the demon.

'Weren't you thinking that humans were predictable? Isn't that what you wanted? For me to show you something interesting?' asked Ciel in detached curiosity.

'Answer my question first creature.' Sebastian hissed angrily

'Humans haven't come up with a name for my kind.' Ciel said, his eyes searching Sebastian for something.

'You're avoiding my question.' Sebastian persisted, taking a threatening step forwards. Ciel simply stood there regarding the increasingly angry demon without any fear.

'I guess there's no real point hiding it any longer.' Ciel said calmly 'I exist to fulfil dreams and desires. I believe humans call it a "symbiotic" relationship; My existence is validated by becoming your fantasy, you get to have all your fantasies brought to life.' The demon continued to stare suspiciously at the boy staring fearlessly back up at him.

'Think about it. Am I not your ultimate fantasy? Physically weak, young and impressionable; the perfect prey for a demon. An innocent soul, stained with dark intentions, naive yet worldly at the same time. A study in contradictions. You enjoy all the word games, the manipulations. Every time you get bored, something interesting happens.'

'I suppose you are.' Sebastian replied with a frown. He took another step forwards, pressing up against the deceptively strong form. One black nailed had shot out and tightened round the slender neck. 'But what happens when I eat you? All creatures strive to live. Choosing me you have chosen death.'

'I will simply be called into being again, my soul residing in that great emptiness where your heart is.' Ciel ran the back of his hand down the side of Sebastian's bewildered face.

'But how can-' The demon was interrupted by a finger.

'Hush. It's not time for you to know, so sleep.'

Before the demon could protest, blackness was crowding his vision and he knew no more.

§§§

Sebastian sat up with a jolt. Had it been one of those strange human dreams? He knew human dreams were often confusing, but this one had been more peculiar than confusing. He looked round his room. Nothing was out of place, but his demonic senses were screaming that something was wrong. A careful comb through of the room revealed nothing.

Dismissing the strange dream Sebastian got up to prepare for the day. After all one hell of a butler couldn't afford to be late for anything.

§§§

Demons are viciously possessive creatures. No not jealous, merely greedy. For there is nothing a human has that a demon would be jealous of. A demon cannot fathom the strange actions of mortals. Nor it is jealous of their souls, for once a soul is in the possession of a demon, it wants another.

However to the outsider the line between jealousy and greed can become one and the same.

It started off with small things, cunning smiles and expressions that Ciel only shared with his butler, were shared with other members of the underground. Sebastian felt the painful flaring of his possessive nature; those looks were for him and only him! Every part of Ciel belonged to him. While the mortal might not know it, every part of him belonged to the demon; from the dark eyelashes to the tiny breaths he exhaled. Sebastian froze for a moment, confused. When had he become so possessive of the young master? He owned Ciel's soul yes, but his body and attention didn't belong to him. Sebastian was dangerously close to the border that all demons stayed away from; the possessive madness that drove demons insane.

However, just because one is aware of something doesn't mean one can do anything about it. Just as a human is aware it breathes and cannot stop breathing; a demon is aware of its possessiveness but cannot stop grasping for more.

For years the demon balanced on this knife edge, sanity on one side, madness on the other. However it was Elizabeth, who proved to be the tipping point.

The young master was sixteen by this time, his hormones at full throttle. Lady Midford had come over for afternoon tea and after much pouting and begging had managed to persuade Ciel to have tea with her in the gazebo. Throughout the afternoon the demon was forced to watch the Lady flirt with his young master and smell the increasing arousal of his young charge. However even more unbearable was the way Ciel had been ignoring his butler the entire day. His possessive flared to unbearable levels, with a cough the butler suggested that if the lady was to make it home by the appropriate time that it might be prudent to take her leave soon. With a startled exclamation Elizabeth bade Ciel farewell and left. Looking a little put out, Ciel dismissed the butler before taking a walk through the rose gardens.

Sebastian watched his master through slitted eyes. He would make sure Ciel's body was his and no-one else.

For months the Butler planned and kept an eye out for his chance. Then a few weeks before his young master's seventeenth birthday, he got it. This was one of the busy times of the year. The final checks would be made for the Valentine's Day products (Christmas products having been approved for manufacture in October). Ciel would often become stressed from the endless reams of paperwork and meetings. Eventually he would cave in and "request" Sebastian work the tension out of his shoulders. Ciel however was extremely stubborn about this, usually only consenting or inquiring about it when the butler alluded to it. However on this occasion his butler said nothing about it. Ciel looked at the demon suspiciously, Sebastian could almost hear the train of thought running through his mind. With a huff Ciel dismissed Sebastian.

The mortal held out for the next three days, most impressive in the eyes of the demon, when he took the boy's fragile constitution into consideration. It finally culminated in the study, not where Sebastian would have preferred, but still suitable for his plans. He had arrived with Ciel's usual afternoon working tea, an Assam tea accompanied by cucumber sandwiches and a small selection of petite fours. Knocking on the door he had received a rather grumpy sounding "Come in."

His master was sitting slumped in his chair, eyes closed, a slight grimace to his face as he lowered one hand from his shoulder.

'I have brought you afternoon tea sir.' The butler said pouring a cup before handing it to his master. Ciel inhaled deeply before taking a sip.

'Is this the new Assam we received from Soma last week?' He asked opening his eyes.

'Your sense of smell is sharp as always.' Sebastian replied with a smile as he placed the two tiered tea stand on one side of the desk. Ciel reached for a sandwich his shoulder popping, causing the young man to wince.

'Are you well my lord? You seem to be a little stiff.'

'It's nothing.' Snapped Ciel. Sebastian sighed inwardly. It seemed Ciel had taken offense to Sebastian not providing him with the little cues to ask for a shoulder massage.

'I hardly think aching muscles are nothing my lord.' Sebastian replied smoothly 'Perhaps a shoulder massage will make your work easier.'

'I suppose it couldn't hurt.' Ciel agreed grudgingly, standing up to allow Sebastian to remove his coat. As his butler neatly hung up the coat on the rack ear the door, Ciel loosened his neck tie as he sauntered over to the window seat. Squinting a little he sat down in the bright sunlight. Walking up silently behind his master the demon placed his hands on the tiny shoulders. Ciel had barely grown since the contract, perhaps time had stopped for him. But whatever the cause, his contractor retained his youthful boyish looks.

As Sebastian's strong fingers kneaded into his shoulders, Ciel imperceptibly relaxed, his shoulders slumping slightly. Patiently Sebastian worked through the muscles of his shoulders and upper back, patiently waiting till his master was relaxed enough. His nostrils flared slightly as he periodically took in his master's scent. Sebastian had almost given up hope that Ciel would actually relax, when the acrid woody smell of tension began to give way to the powdery linen smell of sleepy relaxation. Sebastian grinned to himself; this was even better than he had hoped for.

Slowly he worked his way back to the base of Ciel's neck, occasionally allowing his bare hands to brash against the soft skin. Ciel tensed the first few times, but eventually stopped reacting. Sebastian repeated this process a few more times, his hands touching more skin each time. Finally he slipped his hands completely under the mortal's collar, caressing the lamb soft skin. With a sleepy moan his young charge leant into his touch. Sebastian allowed one hand to snake between the buttons of the wilting white shirt. Slowly, carefully he seduced his young master, the latter opening up to him like one of those white roses he was so fond of.

Gently he took his young master, making sure that he would turn to Sebastian for more in the future. As he made the fragile body sing its pleasure, a smile like that of a wolf at a sheep, dawned across his sculpted features.

Sebastian didn't care anymore. It was perfection, a dream come to life. He just wanted more, everything that was his master, to consume and possess.

Every.

Little.

Bit.

§§§

Sebastian's possessiveness was reaching unbearable levels the aching emptiness in him that strained to reach fulfilment through possession of his master. He possessed his master's body, and his soul was as good as the demons. All that remained was his mind. He wanted to be all his master thought about. But how to do so? He wanted his master to think about him the same what he thought about him. He wanted Ciel to look only for him, search only for his presence.

It would take a long time, but what the demon wants the demon gets. Slowly he crowded his young master, cutting him off from all outside interference. There were times when Ciel was glad for his interference; from preventing Elizabeth from disturbing him in his office, to dragging the childish prince Soma out of his office. However it was not always a smooth process. Ciel deeply resented Sebastian's increasing interference in his investigations. More and more frequently Sebastian would confine him to the townhouse or manor, citing that it was too dangerous. The seasons passed and Ciel's interest in the world beyond his estates was stifled as he came to rely on the demon. Seasons turned into years, and the world moved on without Ciel Phantomhive.


End file.
